Magnesium Ferrite/Polyvinyl Alcohol (PVA) Nanocomposites: Fabrication and Characterization

Terbium doped magnesium spinel ferrites (Mg1-xTbxFe2O4) with composition x=0.12, 0.14, 0.16, 0.18 were synthesized via micro-emulsion method followed by synthesis of PVA/Mg1-xTbxFe2O4 composites using in-situ polymerization technique. The structural properties were evaluated using X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR). XRD analysis confirmed the construction of spinel lattice of terbium ferrite whereas FTIR revealed the interactions between ferrite nanoparticles and polyvinyl alcohol matrix. The XRD and FTIR results quite matched with the reported literature. The dielectric and resistivity analyses were performed by determining dielectric parameters and current-voltage measurements. The values of dielectric constant, dielectric loss and tan ? were found to be inversely proportional to the frequency under the ambient electric field at room temperature but became constant at higher frequency values. The lower values of dielectric constant of terbium incorporated magnesium ferrite polymer composites (MgFe2O4/PVA) are attributed to hindrance in ‘electron exchange mechanism’ created by lockup between iron and terbium ions. The resistivity values of all the composites were found from 2.5x109 ?cm to 18.8x109 ?cm which showed a non- linear behavior.